Selenium

chemistry · elements · minerals

A shape-shifter element. Selenium is super weird because the same element can look completely different depending on how it forms. It can be brick-red powder, shiny like black glass, or metallic gray, like it can't decide what it wants to be.

Discovered in 1817. A Swedish scientist named Jöns Jacob Berzelius found selenium and noticed it acted a lot like another element called tellurium. He thought they were similar enough to give selenium its own special spot on the periodic table.

Rare on Earth. Selenium almost never shows up by itself in nature. Instead, it hides inside other rocks and minerals, which is why scientists had to be really clever to find and identify it in the first place.

Essential for your body. Even though it's rare, your body needs selenium to work properly. It helps protect your cells and keeps your immune system strong, though you only need teeny tiny amounts.